Another Reason to Hate Global Warming: Lousy Coffee

Is the world’s coffee supply threatened by global warming? A recently published scientific study concludes that as much as 99.7 percent of wild Arabica coffee—the bean that accounts for 70 percent of the global market—may fall victim to rising temperatures by 2080. Farmers will still be able to cultivate Arabica coffee—at least for a while—but the bean’s genetic pool will be severely reduced.

The study, conducted by scientists at the Kew Royal Botanic Gardens, in collaboration with Ethiopia’s Environment and Coffee Forum, focuses primarily on Ethiopia, considered to be the birthplace of coffee. Temperatures there have been going up by an average of almost 0.3 degrees per decade since 1960, according to Aaron Davis, head of coffee research at the Royal Botanic Gardens and one of the study’s authors. Soon, he says, ancient Arabica plants may not be able to survive. “It doesn’t take a scientist to realize: Hang on a minute, if coffee can only produce a good crop in a sort of 4 to 5 degree range, [steadily rising temperatures] could have a significant impact,” he says. The optimal temperature range for growing Arabica is 18C to 21C (64F to 70F).

The Kew study shows that wild Arabica beans in South Sudan and Kenya, which exist in smaller numbers than in Ethiopia, will also be impacted. In fact, Davis says the plants in South Sudan, which have been around for thousands of years, may be gone “in the next 10 to 20 years.”

In recent days, some alarmist news articles have interpreted the Kew study to mean devastation for all the world’s coffee beans, as well as the imminent extinction of all lattes and cappuccinos. Davis is careful to point out that this is not the case. Farmers around the world will likely find ways to keep growing the strains of Arabica they already have. What’s at stake is Ethiopia’s wild Arabica, which Davis says is home to anywhere from 80 percent to 98.8 percent of the species’s gene pool. Preserving and transplanting those wild Arabica strains to other locales in mass quantities would be no small task.

If Arabica’s genetic diversity is wiped out, there will be big consequences. “The Arabicas grown in the world’s coffee plantations are from very limited genetic stock,” says Davis. “If you look at the history of coffee cultivation since the 1700s, what’s happened is the industry repeatedly goes back to Ethiopia to sort out its problems, whether they’re productivity issues or simply taste—making a good cup of coffee—you have to have that genetic diversity, that gene pool, to go back to.”

Arabica is one of only two species of coffee, and it accounts for nearly all sales at coffee shops and grocery stores. Robusta, the second species, which is harsher in flavor and contains more caffeine, is found mainly in soluble instant coffees. If climate change eradicates wild Arabica and threatens commercial Arabica production, chances are we’ll be left drinking worse coffee, and perhaps a lot more Robusta. (In fact, soaring coffee prices may already have brands sneakily switching to inferior beans, according to food writer Oliver Strand.)

Coffee is the world’s favorite beverage and the second-most-traded commodity after oil. In 2009-10, coffee accounted for an estimated $15.4 billion in exports and employed more than 26 million people around the world, according to the Kew study. But despite worldwide coffee demand—even obsession—there have been few peer-reviewed studies on coffee and climate change. “Although there are a lot of reports and anecdotal messages from farmers around the world who say they’re being impacted by climate change, there’s almost no peer-reviewed science behind those allegations,” says Davis. What’s needed, he says, is more research, as well as careful management of key areas, especially in Ethiopia.

Called for comment on the study, Starbucks (SBUX) sent only a statement saying: “Our comprehensive approach to ethical sourcing—including farmer support centers, farmer loans, strong standards, and forest carbon programs—promote best practices in coffee production.”